(a) Industrial Field of the Invention
The present invention relates to novel ferroelectric liquid-crystalline polymers and to epoxides that are usable as monomers to preparation of the ferroelectric liquid-crystalline polymer. More particularly, the present invention relates to ferroelectric liquid-crystalline polymers which not only exhibit ferroelectricity even at temperatures around room temperature, but also have such a high speed of response to external factors that they can be used for displaying moving pictures, and are able to be advantageously used as display devices for large displays or curved displays. Such liquid-crystalline polymers are useful in optoelectronics fields as various electronic optical devices, particularly, as display devices for desk calculators, clocks and watches, etc., electronic optical shutters, electronic optical diaphragms, optical modulators, optical-path transfer switches in optical communication systems, memories, liquid crystal printer heads, variable-focal-length lenses, and so forth.
(2) Description of the Related Art
Display devices employing low molecular weight liquid-crystalline compounds have been widely used for digital display in desk calculators, clocks and watches, etc. In these fields of utilization, conventional low molecular weight liquid crystal compounds are sandwiched between a couple of glass substrates, the space between the glass substrates being adjusted with a precision to an extent of micrometers. However, such a precise adjustment of the space has actually been impossible in large displays or curved displays.
In order to solve the problem, it has been attempted to develop polymeric liquid crystals so as to make it possible to mold liquid crystals themselves (cf., J. Polym. Sci., Polym. Lett., Ed. 13, 243 (1975), Polym. Bull., 6, 309 (1982), Japanese Patent Application Laid-open No. 55-21479, etc.).
Nevertheless, the liquid crystal polymers resulting from the above attempts have an disadvantage in that the polymers do not exhibit any liquid crystal properties unless they are heated at temperatures between their glass transition temperatures and their clearing points.
In Japanese Patent Application Laid-open No. 63-99204, disclosed is the synthesis of polyacrylate ferroelectric liquid-crystalline polymers that are confirmed to outperform the above-described liquid-crystalline polymers. However, there is yet room for improvement in the response speed and the utilizable temperature range of the polyacrylate ferroelectric liquid-crystalline polymers.